Ln2GeB2O8 (Ln = Nd, Sm–Tb): a series of luminescent lanthanide(iii) borogermanates with a layered structure

Abstract

A series of new lanthanide borogermanates, namely, Ln₂GeB₂O₈ (Ln = Nd, Sm–Tb), have been synthesized by high temperature solid state reactions in platinum crucibles. They are isostructural and feature a layered [GeB₂O₈]⁶⁻ architecture built of 1D chains of corner-sharing BO₄-tetrahedra that are further bridged by GeO₄-tetrahedra. The lanthanide(III) ions are located at the interlayer space and are seven-coordinated. Results of magnetic measurements indicate Sm(III), Eu(III) and Gd(III) compounds display an antiferromagnetic interaction between Ln(III) centers whereas the Tb(III) compound exhibits a ferromagnetic interaction between Tb³⁺ ions. Luminescent studies indicate that Eu₂GeB₂O₈ and Tb₂GeB₂O₈ emit strong red and green light, respectively.